Nozzle hits the prints but bed is leveled

So, this is something I'm experiencing after flashing Marlin (1.1.9 or 2.0).

I level the bed using Bilinear bed leveling or leveling the 4 corners manually (with bilinear off), and the nozzle will hit the prints always.

What I noticed is that when I'm doing an auto home, just before leveling corners, the nozzle will stay a little bit high. It touches the endstop, but it's higher than when leveling the corners. Also, when printing, it seems the nozzle is even closer to the bed compared to when leveling the corners.

Any ideas as why this happens?

Thanks.

When configuring Marlin there is a few things to remember.

The bed leveling data is a strange thing is seems that unless you restore the data it is not accually using the data.

There are two way to to restore this data.
In your slicer you can add the following line to the end of your Startup G-Code
M420 S1 ; Bed Leveling On

OR

You can enable this line in your Marlin Firmware.
#define RESTORE_LEVELING_AFTER_G28

I use a average amount of data points with a 6 X 6 matrix grid.

Upload your configuration.h and configuration_adv.h file to a share like google Drive, post a link here I or someone else will take a look for you.

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Computer Programmer / Electronics Technician

Sorry I forgot to mention I have M501 and M420 S1 right after G28. I also tried putting it right after the last G29. Same results.

I checked the values with M420 V in Octoprint. All are correct. Bed leveling is ON. I also tried with 10 or 20 Fade.

Here are the files.

[drive.google.com]

[drive.google.com]

Have in mind that I disabled software endstops just for troubleshooting.

Edited 2 time(s). Last edit at 04/05/2020 03:14AM by bornlivedie.

Read this

/** Allen Key Probes, Servo Probes, Z-Sled Probes, FIX_MOUNTED_PROBE, etc.
 *  Activate one of these to use Auto Bed Leveling below.
 */
/**
 * A Fix-Mounted Probe either doesn't deploy or needs manual deployment.
 *   (e.g., an inductive probe or a nozzle-based probe-switch.)

//#define FIX_MOUNTED_PROBE

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Computer Programmer / Electronics Technician

I don't really think that applies to my setup, since I don't have a probe installed.

And, as I said before, I leveled the bed using "Level Corners" with Auto Bed Leveling completely turned OFF in Marlin and the same happens.

The temporary solution I found is to use Baby Steps, but that doesn't even work 100% because for some prints I have to set it to something like 0.050 while others require that I set it to 0.350 or more. That's a HUGE difference...

Quote
bornlivedie

I don't really think that applies to my setup, since I don't have a probe installed.

Sorry I forgot to mention I have M501 and M420 S1 right after G28. I also tried putting it right after the last G29. Same results.

Thought you had a probe because you have this enabled

#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN

I use a M502 Factory Reset and M500 Save Settings and I place M420 S1 After the Last G29.

Not any more I now use

#define RESTORE_LEVELING_AFTER_G28

Quote
bornlivedie

The temporary solution I found is to use Baby Steps,

I had so many starts fail that using Baby steps to start seems 2nd nature unless 1st layer is laying correctly, and have had almost no fail prints sense.

Quote
bornlivedie
I have to set it to something like 0.050 while others require that I set it to 0.350 or more. That's a HUGE difference...

This sounds like your bed leveling adjusters are moving.

Edited 2 time(s). Last edit at 04/05/2020 10:50PM by Roberts_Clif.

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Computer Programmer / Electronics Technician

Quote
Roberts_Clif

Quote
bornlivedie

I don't really think that applies to my setup, since I don't have a probe installed.

Sorry I forgot to mention I have M501 and M420 S1 right after G28. I also tried putting it right after the last G29. Same results.

Thought you had a probe because you have this enabled

#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN

Most likely I enabled that by mistake.

I use a M502 Factory Reset and M500 Save Settings and I place M420 S1 After the Last G29.

Not any more I now use

#define RESTORE_LEVELING_AFTER_G28

Tried that, but fails too.

Quote
bornlivedie

The temporary solution I found is to use Baby Steps,

I had so many starts fail that using Baby steps to start seems 2nd nature unless 1st layer is laying correctly, and have had almost no fail prints sense.

Quote
bornlivedie
I have to set it to something like 0.050 while others require that I set it to 0.350 or more. That's a HUGE difference...

This sounds like your bed leveling adjusters are moving.

As far as I know, they're not. I lowered the endstop from Z so I could lower the bed to the max, making sure the springs were super tight. One thing I noticed (by accident) is that the 4 wheels of the bed where super lose, and the bed was rocking side to side. I adjusted it, made a few prints, no major issues right now, but to be fair, the nozzle was way too far from the bed.

Will update in a few hours with the results.

Ok, it's fixed now. It was the bed all along. Configured Marlin again, with Bilinear Bed Leveling and 9 points distributed across the bed, printed a few things that gave me issues before, and now it's working. Nozzle is not hitting the prints.

Thanks!